With advances in multimedia technologies and network technologies, users have been provided with various services using multimedia devices. To use a service, a user may first be authenticated using, for example, a user's detectable iris information. For user authentication using the user's iris information, the iris of the user has to be photographed. To photograph the iris, a sufficient amount of light needs to be provided. Moreover, to obtain a useful image of the iris regardless of a photographing condition, a sufficient amount of light needs to be irradiated to the user's iris.
A device may irradiate a sufficient amount of light to the iris by using a light source that emits a large amount of light. However, when the iris is close to the device, irradiation of such a large amount of light to the eyes of the user may damage the user's eyes or otherwise cause discomfort to the user. Thus, a proper amount of light has to be irradiated to the user's iris.
Therefore, a device that photographs an iris has to irradiate a proper amount of light to a user according to a position of the user and maintain a degree of user comfort.
The above information is presented as background information only, and to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.